Toyota Tundra Service Manual: Speed Sensor Rotor Faulty (C1237)

Toyota Tundra Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System / Speed Sensor Rotor Faulty (C1237)

DESCRIPTION

The skid control ECU (brake actuator assembly) measures the speed of each wheel by receiving signals from each speed sensor.

These signals are used for recognizing that all four wheels are operating properly.

Therefore, signals from all wheels must be equal.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1237

Speed Sensor Rotor Faulty

Any of the following is detected:

Discrepancy among four wheel speed sensor output.
Abnormal pulse signals from 3 or more sensors.

Tire and wheel size
Tire deformation
Speed sensor rotor
Speed sensor
Speed sensor circuit
Skid control ECU (brake actuator assembly)

WIRING DIAGRAM

Refer to DTCs C1330, C1331, C1332, C1333, C1464, C1465, C1466 and C1467.

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CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration.

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HINT:

When C1330, C1331, C1332, C1333, C1464, C1465, C1466 and/or C1467 is output together with C1237, inspect and repair the trouble areas indicated by C1330, C1331, C1332, C1333, C1464, C1465, C1466 and/or C1467 first.

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PROCEDURE

CHECK DTC

(a) Check that the DTC is output.

Click here

Result	Proceed to
C1237 and C1330, C1331, C1332, C1333, 1464, C1465, C1466, C1467 are output simultaneously	A
C1237 is output	B

GO TO DTCS (C1330, C1331, C1332, C1333, 1464, C1465, C1466 and/or C1467)

2.	CHECK TIRES

(a) Check the size and condition of all four tires.

Click here

HINT:

The DTC is output when tire deformation or a difference in tire size is detected.

OK:

The diameter and tire pressure of all four tires are the same.

REPLACE TIRES SO THAT ALL FOUR TIRES ARE THE SAME SIZE

3.	READ VALUE USING TECHSTREAM (SPEED SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

ABS/VSC/TRAC

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
FR Wheel Speed	Front wheel speed sensor RH reading	Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph)	Vehicle stopped: 0 km/h (0 mph)	When driving at constant speed: No large fluctuations
FL Wheel Speed	Front wheel speed sensor LH reading	Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph)	Vehicle stopped: 0 km/h (0 mph)	When driving at constant speed: No large fluctuations
RR Wheel Speed	Rear wheel speed sensor RH reading	Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph)	Vehicle stopped: 0 km/h (0 mph)	When driving at constant speed: No large fluctuations
RL Wheel Speed	Rear wheel speed sensor LH reading	Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph)	Vehicle stopped: 0 km/h (0 mph)	When driving at constant speed: No large fluctuations

(d) Check the speed sensor output value.

OK:

The output value changes in accordance with the vehicle speed.

Result	Proceed to
OK	A
NG (The output value for 1 front speed sensor does not change in accordance with the vehicle speed)	B
NG (The output value for 1 rear speed sensor does not change in accordance with the vehicle speed)	C
NG (The output value of 2 or more sensors does not change in accordance with the vehicle speed)	D

GO TO STEP 5

GO TO STEP 14

REPLACE BRAKE ACTUATOR ASSEMBLY

4.	PERFORM TEST MODE INSPECTION (SIGNAL CHECK)

(a) Turn the ignition switch off.

(b) Enter the following menus: Chassis / ABS/VSC/TRAC / Utility / Signal Check.

Click here

OK:

All Test Mode (Signal Check) inspection items change from incomplete to complete.

Result	Proceed to
OK	A
NG (The Test Mode (Signal Check) inspection item for 1 front speed sensor does not change from incomplete to complete)	B
NG (The Test Mode (Signal Check) inspection item for 1 rear speed sensor does not change from incomplete to complete)	C
NG (The Test Mode (Signal Check) inspection item for 2 or more sensors does not change from incomplete to complete)	D

USE SIMULATION METHOD TO CHECK

GO TO STEP 5

GO TO STEP 14

REPLACE BRAKE ACTUATOR ASSEMBLY

5.	CHECK FRONT SPEED SENSOR INSTALLATION

(a) Turn the ignition switch off.

*a	Normal
*b	Abnormal
*c	Clearance

(b) Check the speed sensor installation.

Click here

OK:

There is no clearance between the sensor and the front steering knuckle.

The installation bolt is tightened properly.

REINSTALL OR REPLACE FRONT SPEED SENSOR

6.	CHECK FRONT SPEED SENSOR (CHECK FOR FOREIGN MATTER)

(a) Remove the front speed sensor.

Click here

(b) Check the front speed sensor tip.

OK:

The sensor tip is free of scratches, oil, and foreign matter.

NOTICE:

If there is oil or foreign matter on the speed sensor, clean the speed sensor.
If the speed sensor is damaged, replace the speed sensor with a new one.
Check the speed sensor signal after cleaning or replacement.
Click here

CLEAN OR REPLACE FRONT SPEED SENSOR

7.	INSPECT BRAKE ACTUATOR ASSEMBLY (POWER SOURCE CIRCUIT)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

for RH

for LH

Front view of wire harness connector

(to Front Speed Sensor)

(b) Disconnect the b1 or b2 front speed sensor connector.

OK:

No deformation or corrosion.

(d) Turn the ignition switch to ON.

(e) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

for RH

Tester Connection	Condition	Specified Condition
b1-2 - Body ground	Ignition switch ON	5.5 to 14 V

for LH

Tester Connection	Condition	Specified Condition
b2-2 - Body ground	Ignition switch ON	5.5 to 14 V

GO TO STEP 12

8.	INSPECT BRAKE ACTUATOR ASSEMBLY (GROUND CIRCUIT)

(a) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

for RH

Tester Connection	Condition	Specified Condition
b1-2 - b1-1	Ignition switch ON	5.5 to 14 V

for LH

Tester Connection	Condition	Specified Condition
b2-2 - b2-1	Ignition switch ON	5.5 to 14 V

for RH

for LH

Front view of wire harness connector

(to Front Speed Sensor)

GO TO STEP 10

9.	CHECK FRONT SPEED SENSOR ROTOR (CHECK FOR FOREIGN MATTER)

(a) Remove the front speed sensor rotor (front axle with ABS rotor bearing assembly).

Click here

(b) Check the speed sensor rotor.

OK:

The rotor is free of scratches, oil, and foreign matter.

NOTICE:

Check the speed sensor signal after cleaning or replacement.

Click here

HINT:

The front speed sensor rotor is incorporated into the front axle with ABS rotor bearing assembly.
If the front speed sensor rotor needs to be replaced, replace it together with the front axle with ABS rotor bearing assembly.

Result	Proceed to
OK	A
NG (The speed sensor rotor is damaged)	B
NG (There is oil or foreign matter on the speed sensor rotor)	C

REPLACE FRONT SPEED SENSOR

REPLACE FRONT AXLE WITH ABS ROTOR BEARING ASSEMBLY

CLEAN FRONT SPEED SENSOR ROTOR

10.	INSPECT SKID CONTROL SENSOR WIRE

(a) Turn the ignition switch off.

*A	for RH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

*A	for LH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH

Tester Connection	Condition	Specified Condition
b1-1 - Ab2-1	Always	Below 1 Ω
b1-1 - Ab2-2	Always	10 kΩ or higher
b1-1 or Ab2-1 - Body ground	Always	10 kΩ or higher

for LH

Tester Connection	Condition	Specified Condition
b2-1 - Ab1-1	Always	Below 1 Ω
b2-1 - Ab1-2	Always	10 kΩ or higher
b2-1 or Ab1-1 - Body ground	Always	10 kΩ or higher

NOTICE:

Check the speed sensor signal after replacement.

Click here

REPLACE SKID CONTROL SENSOR WIRE

11.	CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE)

(a) Turn the ignition switch off.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH:

Tester Connection	Condition	Specified Condition
A57-26 (FR-) - Ab2-1	Always	Below 1 Ω
A57-26 (FR-) or Ab2-1 - Body ground	Always	10 kΩ or higher

for LH:

Tester Connection	Condition	Specified Condition
A57-37 (FL-) - Ab1-1	Always	Below 1 Ω
A57-37 (FL-) or Ab1-1 - Body ground	Always	10 kΩ or higher

REPLACE BRAKE ACTUATOR ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.	INSPECT SKID CONTROL SENSOR WIRE

(a) Turn the ignition switch off.

*A	for RH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

*A	for LH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH

Tester Connection	Condition	Specified Condition
b1-2 - Ab2-2	Always	Below 1 Ω
b1-2 - Ab2-1	Always	10 kΩ or higher
b1-2 or Ab2-2 - Body ground	Always	10 kΩ or higher

for LH

Tester Connection	Condition	Specified Condition
b2-2 - Ab1-2	Always	Below 1 Ω
b2-2 - Ab1-1	Always	10 kΩ or higher
b2-2 or Ab1-2 - Body ground	Always	10 kΩ or higher

NOTICE:

Check the speed sensor signal after replacement.

Click here

REPLACE SKID CONTROL SENSOR WIRE

13.	CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE)

(a) Turn the ignition switch off.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH:

Tester Connection	Condition	Specified Condition
A57-27 (FR+) - Ab2-2	Always	Below 1 Ω
A57-27 (FR+) or Ab2-2 - Body ground	Always	10 kΩ or higher

for LH:

Tester Connection	Condition	Specified Condition
A57-36 (FL+) - Ab1-2	Always	Below 1 Ω
A57-36 (FL+) or Ab1-2 - Body ground	Always	10 kΩ or higher

REPLACE BRAKE ACTUATOR ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

14.	CHECK REAR SPEED SENSOR INSTALLATION

(a) Turn the ignition switch off.

*a	Normal
*b	Abnormal
*c	Clearance

(b) Check the speed sensor installation.

Click here

OK:

There is no clearance between the sensor and the rear axle carrier.

The installation bolt is tightened properly.

REINSTALL OR REPLACE REAR SPEED SENSOR

15.	CHECK REAR SPEED SENSOR (CHECK FOR FOREIGN MATTER)

(a) Remove the rear speed sensor.

Click here

(b) Check the rear speed sensor tip.

OK:

The sensor tip is free of scratches, oil, and foreign matter.

NOTICE:

If there is oil or foreign matter on the speed sensor, clean the speed sensor.
If the speed sensor is damaged, replace the speed sensor with a new one.
Check the speed sensor signal after cleaning or replacement.
Click here

CLEAN OR REPLACE FRONT SPEED SENSOR

16.	INSPECT BRAKE ACTUATOR ASSEMBLY (POWER SOURCE CIRCUIT)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

for RH

for LH

Front view of wire harness connector

(to Rear Speed Sensor)

(b) Disconnect the b3 or b4 rear speed sensor connector.

OK:

No deformation or corrosion.

(d) Turn the ignition switch to ON.

(e) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

for RH

Tester Connection	Condition	Specified Condition
b3-2 - Body ground	Ignition switch ON	5.5 to 14 V

for LH

Tester Connection	Condition	Specified Condition
b4-2 - Body ground	Ignition switch ON	5.5 to 14 V

GO TO STEP 21

17.	INSPECT BRAKE ACTUATOR ASSEMBLY (GROUND CIRCUIT)

(a) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

for RH

Tester Connection	Condition	Specified Condition
b3-2 - b3-1	Ignition switch ON	5.5 to 14 V

for LH

Tester Connection	Condition	Specified Condition
b4-2 - b4-1	Ignition switch ON	5.5 to 14 V

for RH

for LH

Front view of wire harness connector

(to Rear Speed Sensor)

GO TO STEP 19

18.	CHECK REAR SPEED SENSOR ROTOR (CHECK FOR FOREIGN MATTER)

(a) Remove the rear speed sensor rotor (rear axle hub and bearing assembly).

Click here

(b) Check the speed sensor rotor.

OK:

The rotor is free of scratches, oil, and foreign matter.

NOTICE:

Check the speed sensor signal after cleaning or replacement.

Click here

HINT:

The rear speed sensor rotor is incorporated into the rear axle hub and bearing assembly.
If the rear speed sensor rotor needs to be replaced, replace it together with the rear axle hub and bearing assembly.

Result	Proceed to
OK	A
NG (The speed sensor rotor is damaged)	B
NG (There is oil or foreign matter on the speed sensor rotor)	C

REPLACE REAR SPEED SENSOR

REPLACE REAR AXLE HUB AND BEARING ASSEMBLY

CLEAN REAR SPEED SENSOR ROTOR

19.	INSPECT SKID CONTROL SENSOR WIRE

(a) Turn the ignition switch off.

*A	for RH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

*A	for LH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH

Tester Connection	Condition	Specified Condition
b3-1 - Rb1-3	Always	Below 1 Ω
b3-1 - Rb1-4	Always	10 kΩ or higher
b3-1 - Rb1-2	Always	10 kΩ or higher
b3-1 - Rb1-1	Always	10 kΩ or higher
b3-1 or Rb1-1 - Body ground	Always	10 kΩ or higher

for LH

Tester Connection	Condition	Specified Condition
b4-1 - Rb1-1	Always	Below 1 Ω
b4-1 - Rb1-2	Always	10 kΩ or higher
b4-1 - Rb1-3	Always	10 kΩ or higher
b4-1 - Rb1-4	Always	10 kΩ or higher
b4-1 or Rb1-1 - Body ground	Always	10 kΩ or higher

NOTICE:

Check the speed sensor signal after replacement.

Click here

REPLACE SKID CONTROL SENSOR WIRE

20.	CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE)

(a) Turn the ignition switch off.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH:

Tester Connection	Condition	Specified Condition
A57-33 (RR-) - Rb1-3	Always	Below 1 Ω
A57-33 (RR-) or Rb1-3 - Body ground	Always	10 kΩ or higher

for LH:

Tester Connection	Condition	Specified Condition
A57-30 (RL-) - Rb1-1	Always	Below 1 Ω
A57-30 (RL-) or Rb1-1 - Body ground	Always	10 kΩ or higher

REPLACE BRAKE ACTUATOR ASSEMBLY

21.	INSPECT SKID CONTROL SENSOR WIRE

(a) Turn the ignition switch off.

*A	for RH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

*A	for LH
*a	Front view of skid control sensor wire
*b	Front view of wire harness connector (to Sensor Side Connector)
*c	Front view of wire harness connector (to Vehicle Side Connector)

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH

Tester Connection	Condition	Specified Condition
b3-2 - Rb1-4	Always	Below 1 Ω
b3-2 - Rb1-3	Always	10 kΩ or higher
b3-2 - Rb1-2	Always	10 kΩ or higher
b3-2 - Rb1-2	Always	10 kΩ or higher
b3-2 or Rb1-2 - Body ground	Always	10 kΩ or higher

for LH

Tester Connection	Condition	Specified Condition
b4-2 - Rb1-2	Always	Below 1 Ω
b4-2 - Rb1-1	Always	10 kΩ or higher
b4-2 - Rb1-3	Always	10 kΩ or higher
b4-2 - Rb1-4	Always	10 kΩ or higher
b4-2 or Rb1-2 - Body ground	Always	10 kΩ or higher

NOTICE:

Check the speed sensor signal after replacement.

Click here

REPLACE SKID CONTROL SENSOR WIRE

22.	CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE)

(a) Turn the ignition switch off.

(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

OK:

The connector is securely connected.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

for RH:

Tester Connection	Condition	Specified Condition
A57-34 (RR+) - Rb1-4	Always	Below 1 Ω
A57-34 (RR+) or Rb1-4 - Body ground	Always	10 kΩ or higher

for LH:

Tester Connection	Condition	Specified Condition
A57-29 (RL+) - Rb1-2	Always	Below 1 Ω
A57-29 (RL+) or Rb1-2 - Body ground	Always	10 kΩ or higher

REPLACE BRAKE ACTUATOR ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR

Yaw Rate Sensor (C1234,C1472,C1474)

Low Power Supply Voltage Malfunction (C1241)

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